Recently, there has been an increasing need to support multi-topology in Multi-Protocol Label Switching (MPLS) networks. For example, service providers may desire to assign different level of service(s) to different topologies such that service separation can be achieved in a more nature and simpler fashion. Further, MPLS networks typically include a set of building blocks to establish a label switching network where a point to point label switched path is used for forwarding traffic. In MPLS networks, a label is assigned to represent a set of Forwarding Equivalent Classes (FEC) of the packets, and the mapping of the label and the FEC is signaled along the path the packets travel, therefore the label switched path is established to forward packets.
In addition, the Label Distribution Protocol (LDP) includes a set of messages and procedures used by network elements to inform other network elements of labels to support MPLS forwarding along normally routed paths so that the traffic is forwarded among and through such paths. LDP distributes the mapping of network layer routing information directly to data link layer switched paths, and associates a FEC with a label switched path created. The FEC associated with an Label Switching Path (LSP) specifies which packets are mapped to the corresponding LSP.
Multi-Topology (MT) Routing in Open Shortest Path First (OSPF) describes a mechanism for OSPF protocols to support Multi-Topologies (MTs) in an IP network where the Type of Service (TOS) based metric fields are redefined and are used to advertise different topologies by advertising separate metrics for each topology. Furthermore, MT-IS-IS: Multi Topology (MT) Routing in Intermediate System to Intermediate Systems (IS-ISs) describes a mechanism within IS-ISs to run a set of independent IP topologies.
Accordingly, each of these existing protocols lack the necessary structure and capabilities to support MT in MPLS networks. Hence, there is a need to have systems and methods for supporting MT in MPLS networks and extending the LDP protocol as one of the signaling protocol in MPLS networks to establish and maintain LSP within each of the network topologies.